Chemistry Exam Past Questions and Answers | JAMB, WAEC and NECO

Chemistry is the study of the substances that make up matter. It looks at their properties, how they react with each other, and how these reactions can create new substances.

• Question 651: Ethene reacts with hydrogen bromide to give Options:
  A) CH₂Br₂
  B) CH₃CH₂Br
  C) C₂H₂Br₂
  D) CHBr₂
  Show Answer
  The correct answer is B .
• Question 652: Hydrogen can be displaced from a hot alkaline solution by Options:
  A) Fe
  B) Cu
  C) Ca
  D) Sn
  Show Answer
  The correct answer is A .
• Question 653: The oxidation number of boron in NaBH ₄ is Options:
  A) -3
  B) -1
  C) +1
  D) +3
  Show Answer
  The correct answer is D .
• Question 654: Which of the following bonds exist in crystalline ammonium chloride (NH₄Cl)? Options:
  A) Ionic and covalent
  B) Ionic and co-ordinate
  C) Ionic covalent and co-ordinate
  D) Covalent , co-ordinate and metalllic
  E) Ionic, covalent and metallic
  Show Answer
  The correct answer is C .
• Question 655:

  

  In the graph above, the activation energy of the catalyzed reaction is

  Options:
  A) 100KJ
  B) 300KJ
  C) 250KJ
  D) 200KJ
  Show Answer
  The correct answer is A .
• Question 656:

  What is eutrophication?

  Options:
  A) The release of harmful chemicals into water bodies
  B) The excessive growth of algae due to nutrient enrichment
  C) The presence of heavy metals in water
  D) The formation of oil slicks on water surfaces
  Show Answer
  The correct answer is B .
• Question 657: When hydrogen sulphide and sulphur dioxide are each passed in turn into a solution of potassium dichromate? Options:
  A) both gases change the colour of the solution from yellow to colourless
  B) both gases causes sulphur to be deposited
  C) only hydrogen sulphide decolourizes the solution
  D) only sulphur dioxide deposits sulphur
  E) only hydrogen sulphide deposits sulphur
  Show Answer
  The correct answer is E .
• Question 658: What is the volume of oxygen required to burn complete 45 cm³ of methane at s.t.p? Options:
  A) 135.0 cm³
  B) 180.0 cm³
  C) 45.0 cm³
  D) 90.0 cm³
  Show Answer
  The correct answer is D .
• Question 659: The reaction of an alkanol with an alkanoic acid in the presence of concentrated H₂SO₄ will produce an? Options:
  A) alkanal
  B) alkanoate
  C) alkanone
  D) alkyne
  Show Answer
  The correct answer is B .
• Question 660:

  A chemical process in which there is a gain of electrons is known as?

  Options:
  A) Sublimation
  B) Reduction
  C) Oxidation
  D) Distillation
  Show Answer
  The correct answer is B .